# a = int(input('请输入第一个整数：'))
# b = int(input('请输入第二个整数：'))
# if a == 1:
#     if b == 2:
#         print('hello')
#     print('programmer')
# print('bai')

# a = int(input('请输入你微信余额:'))
# if(a <= 1000):
#     pass
# else:
#     print('去长沙旅游')

# #1-100的和
# num = 1
# result = 0
# while num <= 100:
#     result += num
#     num += 1
# print(f'result = {result}')

# #打印 1-10 的整数
# num = 1
# while num <= 10:
#     print(num)
#     num += 1

# #计算 5 的阶乘
# num = 1
# result = 1
# while num <= 5:
#     result *= num
#     num += 1
# print(f'result = {result}')

# i = 1
# for i in range(1 , 11):
#     print(i)

# i = 1
# for i in range(2 , 12 , 2):
#     print(i)

# sum = 0
# for i in range(1 , 101 , 1):
#     sum += i
# print(sum)

# for i in range(1 , 10):
#     if i % 2 == 0:
#         break
#     print(i)

count = 0
sum = 0
while True:
    num = input('请输入数字：')
    if num == ';':
        break
    num = float(num)
    sum += num
    count += 1
print(sum / count)

